1. Field of the Invention
This invention relates to an extra lightweight non-load bearing building block, specifically for construction of interior building partitions or other non-load bearing interior walls. The block may be formed into standard or modular size building blocks similar in shape to commonly used concrete blocks, cellular or solid form.
2. The Prior Art
Heretofore, various types of concrete blocks have been manufactured and commonly used in construction for many years, such as cinder concrete block, stone concrete blocks and lightweight concrete blocks. The cinder concrete block, used in many instances for load-bearing, has lost favor in the construction industry because of its' structural instability. The stone concrete block and lightweight concrete block are used for their load-bearing capabilities and in certain cases the lightweight concrete block is used for partitions. Because of weight however, existing lightweight concrete blocks are not commonly used for partitions and have been replaced by gypsum wall board or sheet rock partitions made of steel or wood studs and faced on both sides with gypsum wall board or sheet rock.
Existing lightweight concrete blocks are manufactured of expanded aggregates known as SOLITE, NYTRALITE, PUMICE, EXALITE and WAYLITE and are manufactured in standard and modular sizes, in cellular and solid form. SOLITE, NYTRALITE, EXALITE and WAYLITE are trade names for expanded shale. PUMICE is a variety of volcanic glass, full of minute cavities and very light in weight. These blocks are manufactured by using expanded shale or PUMICE, sand, cement and water in various mixes. The average weight of these commonly used lightweight blocks using a nominal 4 .times. 8 .times. 16 inches, three celled block as an example, range from 16.5 pounds to 18.2 pounds each, with an average weight, in place, in a wall including cement joints of 21 pounds per square foot.
Lightweight aggregates including perlite as an ingredient with clay are well known in the art, as evidenced in U.S. Pat. Nos. 2,699,409, and 2,728,733. Further building material employing expanded perlite, Portland cement and hydraulic binder with an additive is also well known, as evidenced in U.S. Pat. Nos. 2,858,227 and in 3,847,633 using additional aggregates and hydraulic binders.